pounce wrote on Thu, 04 November 2004 19:30 |
Sahib wrote on Thu, 04 November 2004 14:13 |
pounce wrote on Tue, 02 November 2004 18:56 | so i'll put the question out this directly. if i can only afford one of the following, which would be most advisable for clean power in a personal project studio...
isolation transformer
balanced power supply
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Balanced power supply as it also provides complete isolation from the mains.
However, you have to be very very careful with balanced power supply in terms of wiring and grounding of your studio.
Cemal
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i'm sure you are right. i would have one of my electrician friends help do the install. it looks like balanced power and a star ground system are a good idea. even for my modest personal project space. but what do you think i should bear in mind for this transition? what concerns should i have? i'd appreciate any info.
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Paul,
John has covered so much that I do not think I can add very much. However, before you think of using any isolation transformer or balanced power supply there are very basic things that you should do.
First is to have a completely seperate power line straight from the main distribution panel (where the meter is) to your studio.
The cable for this line should be 2 cores for live/neutral + metal shield-screen for earth connections ( for single phase). As John mentioned the neutral should be completely isolated from the main distribution panel chasis.
Also the route that this line follows is very important. Although it is screened, still avoid running it next to other lines. You should make sure that there is at least 8-10 inch distance between them
No lights, no coffee machines etc. to be connected to this line. Nothing but only your recording gear. You must have a complete isolation.
Coffe machines, photocopiers, printers are the main source for causing harmonic distortion on the mains. As harmonic distortion effects the performance of transformers, any equipment that utilises transformer on its power supply stage will be effected in some way.
The lights are also important. No fluorescant lighting or lighting that uses electronics/dimmers etc. in the studio, even though they operate on a completely seperate power circuit. They are the source for RF noise. Just use simple tugnsten or halogen lighting but mains only.
Once you do that you can be sure that you now did everything you can to bring the power to your studio with minimal exposure to external polluting factors. Well, there is one more which is having a dedicated earth completely seperate from the one that is provided by your electricity supplier. However,since you are operating from home this is out of equation.
Now you have the power in your studio and trying to make a decision on whether you should go for the isolation transformer or balanced power supply.
My choice would be to use a balanced power supply as I mentioned before it also provides isolation from the mains. But on the other hand John's recommendations on some equipment not liking it should be seriously taken into consideration. Again as I mentioned before connecting your equipment to the balanced power supply requires extra care. Text book precautions such as star grounding etc. should be followed. Also do not forget no filtering system will help the hiss and hum that is generated by the electronic circuitry of your equipment.
We have a small project studio. We wanted to use a balanced power supply but wiring regulations do not allow it in the UK. So we did our own mains isolation and filtering. We used two identical transformers wired back to back with RC filter in the middle. We made 3 seperate units, supplying to PC, monitors and the outboard all seperately and it works fine and our system is definitely running quiter but it does not provide a complete isolation.
Cemal